Even though the average temperature dropped by four degrees last week, October remains much warmer than normal.
The average temperature for the first two weeks of the month now stands at 14.5 degrees Celsius, down from 18.8 C at the end of the first week but still way above 9.4 C, which is the normal average for the entire month. The above-normal average temperature is entirely due to the heat wave during the first few days of the month when daytime highs hit 30 C. Since then, temperatures have been slightly below normal with lots of cloud cover.
There were just a few millimetres of rain, bringing the monthly total to 109 millimetres. This is about 25 per cent above normal for the entire month but in reality, it just makes up for the dry spell that we experienced in September. The tile drains have reduced to a trickle after the deluge at the beginning of the month and the soil is moist enough that the winter wheat, planted after the soybean harvest, has started to sprout.
With the warmer temperature, the corn heat unit (CHU) count has already surpassed the normal for the entire month. There have been 205 CHU so far in October, while the normal for the entire month is 146 CHU. Despite the continuing increase in heat units, the impact on corn yields is likely to be negligible this late in the season. Since the May 11 start date for the local heat unit count, the total recorded so far is 3,378 CHU for the 2023 cropping season, which is above the 10-year average of 3,189.
The normal date for the first killing frost is now October 16, which is 11 days later than it was 30 years ago. However, there are no nighttime temperatures close to a killing frost forecast until the fourth week of the month has started.